Electrical measuring instrument.



No. 737,255. PATENTED A'UG.25,1903.

w. J. LLOYD. I

ELECTRICAL MEASURING INSTRUMENT.

APPLICATION FILED FEB. 10, 1903.

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H0 MODEL.

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No. 737,255. PATEN'IED AUG. 25, 1903.

w. J. LLOYD.

ELECTRICAL MEASURING INSTRUMENT. APPLIUATIOH FILED FEB. 10, 1903. H0MODEL. 2 SHEETS-SHEET 2.

1N VEN TOR.

WITNESSES;

W091? I I I ALI/ATTORNEYS? I UNITED STATES Patented August 25, 1903.

PATENT OFFICE.

WILLIAM J. LLOYD, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO STANLEYELECTRIC MANUFACTURING COMPANY, OF PITTSFIELD, MASSACHUSETTS, ACORPORATION OF NEW JERSEY.

ELECTRICAL MEASURING INSTRUMENT.

SPECIFICATION forming part of Letters Patent No. 737,255, dated August25, 1903. Application filed February 10, 1903. Serial No. 142,776. (Nomodel.)

T0 on whom it may concern.-

Be it known that I, WILLIAM J. LLOYD, a citizen of the United States,and a resident of Pittsfield, Massachusetts, have invented certain newand useful Improvements in Electrical Measuring Instruments, of whichthe following is a specification. 7

The object of my invention is to provide an instrument for measuringelectric currents that shall be suitable for both alternating and directcurrents, that shall not be affected by frequency or wave form, thatshall be sensitive and accurate thoughout its range, that shall bedead-beat in its indications, that shall allow of ready and accurateadjustment, that shall be portable, and that shall be simple andeconomical in construction.

Referring to the drawings, Figure 1 is a front elevation, and Fig. 2 isa side elevation of an instrument embodying my invention.

A is a stationary coil so formed that its inner surface is practicallyspherical. This coil may be a casting, as indicated in the drawings, orit may be wire-wound.

B is a light annular coil rotatably mounted within the sphericalinterior of stationary coil A. Coil B is preferably mounted like thebalance-wheel of a Watch, pivoted on jewelbearings C C and opposedin itsrotation by the spiral springs D D. The outer ends of springs D D areattached to arms E E, and arm E is carried by adjustable plate F, whichpermits adjustment of the spring tension. This method of mounting andadjustment, which is precisely similar to that employed in a watch andwhich needs no further description, furnishes a delicate constructionand renders the instrument at the same time sensitive and portable.

Carried bythe movable coil B is a light pointer H, which is adapted tomove over the scale-plate I. Also carried by movable coil 13 is arm J,carrying at its end the vane K, which moves in chamber L as coil Brotates and acting as an air dash-pot damps the motion of coil 13 andrenders the indications of pointer H dead-beat. Arm N and counterweight0, adjustable thereon, are also carried by movable coil B and furnish asupplementary means of adjustment of the movable coil.

The spherical chamber formed by coil A provides an intense and uniformfield for all positions of coil B, and hence renders the instrument moreevenly sensitive throughout its range than in former instruments. Therebeing no iron in the magnetic circuit of either coil, theinstrument iscorrect for alternating as well as direct current and is not affected byfrequency or wave form.

The instrument is suitable for measuring many of the characteristics ofelectric currents. When used as awattmeter, the sta tionary coil A willbe connected in the .line, either directly or by means of ashunt or aseries transformer, while the movable coil B will be connected acrossthe line through a non-inductive resistance ora potential transformer,or both. When a non-inductive resistance is used, it may be convenientlycarried by bobbins mounted inside the case, as indicated at M M. 1 7T0avoid friction due to moving contacts, springs D D are preferably Whenthe instrument is used as an ammeter,

both coils may be connected in the line in shunt to each other or in anyof the ways wellknown to those skilled in the art to whom the varioususes of the instrument will be obvious.

I do not desire to limit myself to the precise constructionandarrangement of parts here shown, as changes therein which do not departfrom the spirit of my invention will be obvious to those skilled in theart.

I claim as newand desire to secure by these Letters Patent-- 1. In anelectrical measuring instrument, a stationary spherical coil, a coilrotatable therein, and means for indicating the position of therotatable coil.

2. In an electrical measuring instrument, a stationary spherical coil,an annular coil rotatable therein, and a pointer carried by therotatable coil.

8. In an electrical measuring instrument, a stationary spherical coil,an annular coil pivotally mounted therein and spiral springs foropposing the rotation of the annular coil.

4. In an electrical measuring instrument,'av stationary spherical coil,acoil rotatable therein, spiral springs opposing the rotation of the 100rotatable coil, and means for indicating the rotation of the rotatablecoil, an air dash-pot position of the rotatable coil. damping themovement of the said coil, and 5. I11 an electricalmeasuring instrument,a a pointer for indicating the position of the stationarysphericalcoil,a coil rotatable theresaid coil. I 5

5 in, spiral springs opposing the rotation of the Signed at Pittsfield,Massachusetts, this rotatable coil, means for damping the move- 2d dayof February; 1903. ment of the rotatable coil, and means for in- I Tdicating the position of the rotatable coil. LL01 6. I11 an electricalmeasuring instrument, a \Vitnesses: IO stationary spherical coil, anannular coil 170-1 RICHARD EYER,

tatable therein, spiral springs opposing the R. E. HAYNES.

